You are configuring a PPP connection between two routers, R1 and R2. The password for the connection will be poppycock. When you are finished you execute the show run command on R1 to verify the configuration.

Which of the following examples of partial output of the show run command from R1 represents a correct configuration of PPP on R1?

A. enable password griswaldhostname R1username R1 password poppycockinterface serial 0/0ip address 192.168.5.5 255.255.255.0encapsulation pppppp authentication chap
B. enable password griswaldhostname R1username R1 password poppycokinterface serial 0/1ip address 192.168.5.5 255.255.255.0encapsulation pppppp authentication chap

C. enable password griswaldhostname R1username R2 password poppycockinterface serial 0/0ip address 192.168.5.5 255.255.255.0encapsulation pppppp authentication chap

D. enable password griswaldhostname R1username R1 password griswaldinterface serial 0/0ip address 192.168.5.5 255.255.255.0encapsulation pppppp authentication chap

Explanation:

The correct configuration is as follows:

enable password griswald
hostname R1
username R2 password poppycock
interface serial 0/0
ip address 192.168.5.5 255.255.255.0
encapsulation ppp
ppp authentication chap

The key settings that are common problems are as follows:

● The username is set to the hostname of the other router (in this case, R2)
● The password is set poppycock which must be the same in both routers

The following set is incorrect because the username is set to the local hostname (R1) and not the hostname of the other router (R2):

enable password griswald
hostname R1
username R1 password poppycock
interface serial 0/0
ip address 192.168.5.5 255.255.255.0
encapsulation ppp
ppp authentication chap

The following set is incorrect because the password is misspelled. It should be poppycock, not poppycok.

enable password griswald
hostname R1
username R1 password poppycok
interface serial 0/0
ip address 192.168.5.5 255.255.255.0
encapsulation ppp
ppp authentication chap

The following set is incorrect because the password is set to the enable password of the local router (R1) rather than the agreed upon PPP password, which is poppycock.

enable password griswald
hostname R1
username R1 password griswald
interface serial 0/0
ip address 192.168.5.5 255.255.255.0
encapsulation ppp
ppp authentication chap

Objective:
WAN Technologies
Sub-Objective:
Configure and verify PPP and MLPPP on WAN interfaces using local authentication

References:
Cisco > Home > Support > Technology Support > WAN > Point-to-Point Protocol (PPP) > Design > Design TechNotes > Understanding and Configuring PPP CHAP Authentication